1. Field of the Invention
This invention relates to a new and improved swath or catamaran type vessel, and more particularly to a new and improved forward deck construction for the above water superstructure for such vessel.
2. Description of the Related Art
The term "swath" is an acronym for Small Waterplane Area Twin Hull. Conceptually, these types of vessels date back to the last century and are characterized generally as comprising two submerged parallel propulsion torpedo-like pontoons, each of which is provided with one or more vertical struts which project upwardly a substantial distance above the water line and which at their upper ends support the entire superstructure of the vessel. In general, the combined buoyancy of the two (or more) propulsion pontoons is sufficient to support the superstructure of the vessel a predetermined distance (e.g., 5-8 feet) above water level while the boat is at rest as well as when it is under way in relatively calm waters. It is well known to provide swath vessels with underwater horizontal stabilizers or canards to assist in maintaining stability of the boat in terms of pitch, roll or yaw while moving at medium to higher speeds either calm water or rough waters.
The above water superstructure of a swath may be designed and outfitted to function in all substantial respects as a conventional mono-hull boat or ship, either primarily as a cargo or passenger carrying vessel. During more recent years, a number of passenger carrying swath vessels ranging in length from around 60 feet to over 200 feet have been built and tested or operated as ocean or seagoing vessels with reasonable success.
To our present knowledge, all of the reasonably well designed swaths that have been built and operated within the past decade provide much enhanced riding stability over any known conventional hull or catamaran construction. A properly designed swath inherently provides a much more "level" ride as far as minimizing the amount of pitch and roll inherent in more conventional designs. However, one severe shortcoming that has been encountered by certain swath vessels is that when the vessel at relatively high speed encounters even moderately rough head seas (involving as little as 10 foot seas) the bow of the swath super-structure tends to plough into the oncoming waves and become submerged in green water, creating the danger of swamping and even sinking of the vessel.
In the conventional boat deck construction, including mono-hulls, catamarans and more conventional swath vessels, the decking itself is made of impervious planking or other form of decking material. Means for draining excess water from deck surfaces are conventionally provided by rain scuppers and green water freeing ports. These side ports or water drains function effectively to drain off rain water and fair amounts of green water even on swath and catamaran vessels. However, if and when the foredeck of the such a vessel becomes submerged under a cresting wave or becomes totally inundated by green water, the side openings of the scuppers and freeing ports are almost useless in giving prompt relief from the weight of the inundating water exerting downward pressures on the foredeck and bow. The inherent buoyancy of the vessel to upright itself within safe time limitations is greatly inhibited. In one instance of which we are aware, the foredeck of a swath vessel submerged by plowing into a oncoming wave at high speed had to be extricated by reversing the engines and literally backing the vessel out from under the mountain of water weighting down the foredeck at a dangerously pitched angle.